Giatsu WD2N8B Serie Manuel De L'utilisateur Et D'installation page 81

Space heating
All units can operate in space heating mode. The operation mode and setting temperature are set on the user interface.
Due to changes of the outdoor temperature and the required load indoors, multiple outdoor units may operate at different
times.
The AHS function is set on the user interface.(AHS function can be set valid or invalid in "OTHER HEATING SOURCE"
of "FOR SERVICEMAN".);AHS is only controlled by master unit. When master unit operate in heating mode, AHS can
be used for heating mode.
2)
1. Maximum 6 units can be cascaded the system. One of them is master unit, the others are slave units; Master unit and
slave units are distinguished by whether connected to wired controller while powering on. The unit with wired controller is
master unit, units without wired controller are slave units. While installation, please check the cascade system diagram and
determine the master unit; Before powering on, remove all wired controllers of salve units.
2. SV2, SV3, P_O, T1, TW2, Tbt, AHS interface are only connected to corresponding terminals on main board of master
unit.
3. The address code of the slave unit needs to be set on the hydraulic module PCB board DIP-switch (See electrically
controlled wiring diagram on the unit)
4. It is suggested to use the reversed return water system in order to avoid hydraulic imbalance between each unit in a
cascade system.
1. In cascade system, Tbt sensor must be connected to master unit and set Tbt vaild on user interface，otherwise all slave
units will not work.
2. If outside circulation pump need to be connected in series in system when the head of internal water pump is not enough,
outside circulation pump is suggested to be installed after the balance tank.
3. Please ensure that the maximum interval of power-on time of all units doesn't exceed 2 mins, which may cause the slaves
to fail to communicate normally.
4. Maximum 6 units can be cascaded in one system, all slave unit address codes cannot be the same and caonnot be 0#.
5. The outlet pipe of each unit must be installed with a check valve.
8.4 Buffer tank volume requirement
NO. Model
1 5~9 kW
2 12~16 kW
3 Cascade system
n: The outdoor unit numbers
Buffer tank(L)
≥ 25
≥40
≥40*n
16